Printing element for typewriter printing machines



Jan. 10, 1950 A. THOMAS 9 3 PRINTING ELEMENT FOR TYPEWRITER PRINTING MACHINES Filed March 16, 1944 2 Sheets-Sheet 1 Inventor ARTHUR THOMAS y jyL A tiornev Jan. 10, 1950 A. THOMAS 2,494,014

PRINTING ELEMENT FOR TYPEWRITER PRINTING MACHINES Fild March 16, 1944 2 Sheets-Sheet 2 F/GZ F/ G. /O

VIII/ m mm W 4 /8 Inventor ARTHUR THOMAS Byypl (an .4 ttorney fiatented Jan. 10, 1956 PRINTING ELEMENT FOR TYP E WRITER A PRINTING MACHINES Arthur Thomas, Wallington, England, assignor to Powers-Samas Accounting Machines Limited, a.

British company Application March 16, 1944, Serial No. 52 ,743

In Great Britain March 27 1943 8 Claims. (01. 101- 109) This invention relates to typewriter printing machines of the kind in which each printing element carries a plurality of type elements and the type elements are positioned in a rigid solid holder for printing by slidably moving the printing elements longitudinally, printing being effected by. a type hammer which is actuated to strike the positioned type element.

'Qne object of the invention is to provide a construction of printing element which will provide slide and limiting seat portions for the type and enable a reduced lateral pitch of the printed characters to be achieved thereby facilitating the feeding of the paper and the manipulation of the ink ribbon and effecting an economy in printing.

A further object is to reduce the pitch of the type elements along the printing element whereby a higher speed of operation than hitherto can be attained for a given number of typeelements give an even printing impression, to provide for the individual removal of any type element or its spring without removing the type bar and to provide an arrangement of type elements that are flush with the sides of the type bars so that the latter can be arranged alongside each other in sliding relation as shown in Fig. 19 of Patent 2,323,816.

According to the present invention a printing element for a typewriter printing machine of the above kind comprises in combination a type holder in the form of a rigid one piece bar of rectangular cross section cut away to form. a longitudinal step or limiting shoulder and a slide seat portion extending along one of the wider faces of the bar and parallel to the narrower faces thereof, and a plurality of type elements, 1 each in the form of a rectangular block having 7 a thickness equal to the thickness of the holder bar and having a type face at one end, the other end of each block being cut away complementally to the longitudinal step or shoulder formed on the bar and the complementary faces of the holder and blocks engaging one another, when the device is assembled, to prevent turning of the blocks relatively to the holder, each block being i an abutment on the shank 2 provided with an axial shank passing through a hole formed inv the bar parallel to the longer axis of its cross section. 1

In a modified embodiment ofthe invention the type holder may be in theform of a single piece bar of rectangular cross section cutaway on both sides to form twolohgitudinal shoulders, one ateachside ofja rib formed by the material of the bar which remains" after the cutting opera tionand presents slidejsea'ts, and each typeelement may be in the' form of a rectangular block having a thickness equal to the thickness of the holder bar and having atype i ace at one end, the other end .of each block being formed with i a slot complementary to the 'rib on'the bar so thatsaid rib will fit into said slot to provide 'a sliding fit andprevent turning of the type element relatively to the holder, each block being, as before, provided with an axial shank passing,

through a hole formed in the bar parallel to the lo'nge'raxis of its cross section. I,

The shank projects beyond the plane edge of the bar and preferably there is provideda spring surrounding the shank between said edge and With such a construction the type element is free to' move relatively to the bar. when struck by a hammer and the interengagement of the step formed by the' cutting away of the holder bar with the correspondingly formed step on the type element, or in themodification referred to. above, the engagement of the slot in the type element with the ribion' the holder effectively prevents rotation ,of the type element, While l avoiding the use of guide members such as slotted type caps, which increase the pitch of the type and: the weight of the type carrier as a Whole.

InQorder to reduce the pitch of the type holders laterally and thereby" obtain closely spaced printed characters, the type holder'bar isfmade equal only to the width of the actual type face on the type element and the shank on the type element passing through the hole in the holder ;bar serves to retain the type element and toguideit'without involving any proof travel must be kept'relatively short. In con structions according to the present invention the shank portion- 01: the type-element permits the type to be positioned in abutting relation along the bar so that the pitch of the type along the bar is only equal to the height of the type element together with a small additional amount required to give the necessary clearance to permit easy 'movement.

Accordingly the present invention permits a lateral pitch of the type as small as 0.1 inch and a longitudinal pitch along the type bar also as small as 0.1 inch. Consequently in a type holder capable of printing 40 characters the length occupied by the actual type elements is only about 4 inches and as many as 65 type holders may be arranged side by side over a width of as little as 6.5 inches so that a line of 65 characters may be printed in a length of 6.5 inches on the paper.

In order that the invention may be more completely understood two embodiments thereof will now be described by way of example with reference to the accompanying diagrammatic drawings in which 7 Figure 1 shows one form of complete type holder in a side elevation with the type elements in position therein;

Figure 2 illustrates the type holder in'front elevation;

Figure 3 is a view to alarger scale of the type holder bar drilled with holes to receive the shanks of the type elements and cut away toform the shoulder above referred to;

Figure 4 is a view to a larger scale of the type holder with type elements in position;

Figure 5 shows one of the type elements of Figure 4 to a larger scale;

Figure 6 is a cross section on the line VI- -VI of Fig. 5;

Figure 7 illustrates a modified form bar; I V

Figure 8 illustrates a type element for use with the holder shown in Fig. '7;

Figure 9 is a cross section of Fig. 8 and Figure 10 shows in end elevation the holder of Fig. 7 with a type element according to Fig. 8 in the assembled condition. 7 V

In the embodimentshown in Figures '1 to 6 of holder on the line Di -IX the type element is made from a short length of rectangular steel bar of which the crosssec-j tion has the same dimensions as the required type face.

The type element l first has the type character formed on one end constituting the type face 2; and is then drilled' centrally at the other end with a hole 3 (see Figure 5) 'to take a cylindrical shank'member 4 constituted by. a lengthof plain steel rod. 7 C

The shank member} not only has to guide the type element I but also has to receive the ham merblow and therefore must be of a considerable thickness in relation to the pitch of the type."

Accordingly the diameter of the shank meme ber 4 may be approximately five-eighths of the." width of the narrower face of the steel bar used for the type element, that is to say about fiveeighths of the lateral pitch of the type.

The bar 1 f orming the type holder is a single piece of stock drilled with a number of holes 8 (Figure 3)., each to receive a shank of a type element, these holes being drilled centrally through the type holder bar. The bar is then undercut to form a longitudinal step or shoulder 9 by milling away the material thereof, the cutaway portion breaking into the holes already drilled in the bar (seerFig. 3).

- The cut-away portion of the type holder bar is rectangular in cross section so that, after the cut-away portion has been removed, if the bar is held horizontal with the cut-away or slide seat portion underneath it will,'in cross section, present an overhung shoulder 9 or limiting seat portion; the thickness of the portion ll! above the shoulder being equal to the original thickness, while the thickness of the portion it below the shoulder is reduced and in this lower portion below the shoulder the side walls'of the holes to receive the shanks are broken into, exposing the interior of the passages formed by the holes.

The portion 8a of each hole which remains, when viewed in cross section, is greater than a semi-circle so. that the hole can still embrace and guide the shank of a type element inserted into receive the shank 4 a portion thereof is milled away commencing from the end remote from the type face, this cutting away operation resulting in the removal of a portion of the type element l which is complementary to the portion of the type'holder 7 which'. is cut away to provide the slide and limit seatfportions.

This cutting away of the type element also 'ex-' poses the hole 3 drilled'therein for a part of the length of said hole, the crosssection of the exposed part 3a of the hole being less. than. a

semi-circle 6). I

The shank 4 is then inserted in" the remainder and constitutinga channel (see Fig.

of the hole 3 which is still of full diameter and on emerging from that hole lies in the channel,

formed by the exposed part 3a of the hole.

The-shank 4 and type element 'I are thenv united in a copper brazing electric furnace which makes alse'cure joint without distorting the ma-. terial or leaving surplus material round the joint.

The shank 4 is then inserted in the hole 8 in a slider which can move transversely of the type the hammer may strike. Each element having its own spring l5 will yield with the same resistance under the force of the hammer blow and all type impressions will be uniform. V

Bythu's milling the holder and type element,

rotation of the. type is prevented without weakening any of the elements or reducing the main guiding length of the hole 8 in the holder since although part of the guide hole in the holder 'in Figs. 7-10 the singlepiece type holder bar I is removed, the remaining part 8a is greater than a semi-circle and therefore is still able to embrace and guide the shank 4.

'In the modified form of the invention shown is cut away on both sides to form two shoulders Qqconstituting limiting seat portions, one at each side of a'ribl la formed by the material of the bar which remains after the cutting operation.

; As before the bar is drilled with a number of holes 8 disposed centrally of the bar, the cut awayportions of the bar constituting slide seats and breaking into the holes oneach side, thereby leaving pairs of channelslla (Fig. '7).

. Each type element I is, as before; drilled centrally at '3 toreceive a shank 4 and is formed with a central slot [8 in its end remote from the type face 2, this slot being co-axial with the hole 3 but ofa width less than the diameter of the hole, so that each wall of the slot has a channel 3a of arcuate cross section extending down its length. The depth of the slot is less than the depth of the hole so that, below the bottom of the slot the hole remains of full diameter.

The slot 18 is complementary to the rib Ila on the type holder 1 so that the rib on the type holder will fit into this slot in the type element and prevent turning of the latter. After the slot l8 has been formed the shank 4 is pushed down the slot into the full diameter portion of the hole 3 which extends below the bottom of the slot, the surface of the shank engaging in the channels 3a formed in the walls of the slot by those portions of the hole 3 which remain after the slot has been formed. The shank and type element are then united as before in a copper brazing electric furnace.

The shank is then inserted in the hole 8 in the type holder and pushed up through the hole until the faces Ma of the type element at each side of the slot 18 abut against the shoulders 9a on the type holder, the slot engaging over the rib Ila formed by the cutting away of the type holder, and the shank '4 being guided by the pair of channels 841 in the rib Ha. I

As before a spring 15 is then threaded over the shank 4 and a collar I6 is passed over the shank above the spring and the free end of the shank is then pressed into a rectangular shape I! to retain the collar in place.

It will be understood that in this modified construction the cutting away of the type holder bar leaves the type holder completely symmetrical in cross section.

By constructions according to the invention a correct guiding of the type is obtained while avoiding the use of solid type caps or any fitting of rectangular members.

Moreover, since the guiding shank 4 is of substantial diameter and as it is central with respect to the type, it receives the hammer blow in direct line with the type so that there are no bending stresses set up by the hammer blow. Also, by pinching the edge of the flattened end I! of the shank, the collar l6 and spring 15 may be removed and any type element can be pulled out of the bar for replacement without disturbing or moving the other bars.

Further since the type elements I are of the same thickness as the holder bar 1 and the guide shank 4 is central of the type elements there are no portions projecting beyond the type bar, the faces of which are quite flat and smooth so that when a number of these bars are operating together they can slide smoothly.

If desired the springs on the type elements may be omitted where the type holders according to the invention are used in those types of machine in which the platen or the type holders are mechanically retracted between printing strokes to bring the type clear of the paper or of the ink ribbon.

I claim:

1. In a type carrier, in combination, a bar having guide bores extending therethrough and spaced longitudinally thereof, said bar being'reduced in, thickness in. a. portion of itswidth-to provide a slide seat, the sides .of the bores opening into said seat, contiguously mounted' type elements-each presenting a block and a guide shank, the block having a portion reduced in thickness complementally to the reduced portion of. said bar andv engaging the said seat thereof for sliding movement when the" shank is in a bore. 2..In a type carrier, in combination, a bar having guide bores extending therethrough' and spaced longitudinally thereof, part of said bar being reducedin thickness to provide a limit seat, the sides of the bores opening into said reduced part, contiguouslymountedtype elements each presenting ablock and a guide shank, the-block having a portion of reduced thickness arranged to fit and be held in said reduced part when the shank is in abore, and a spring onsaid shank for yieldably maintaining the block against said limit seat.

3. In a type carrier, in combination, a bar having bores spaced longitudinally thereof, a part of the bar being reduced in thickness to present slide seat and limiting seat portions, contiguously supported type elements each presenting a block and a guide shank, the block being slotted complementally to the reduced part of the bar and being arranged to engage the slide seat and limit seat portions when the guide shank is engaging in a bore, and means on the shank for yieldably maintaining the block against said limit seat portions.

4. In a type carrier, in combination, a bar having bores spaced longitudinally thereof, a part of the bar being reduced in thickness to present a flat slide seat into which the side of said bores open, type elements each presenting a block having a portion of reduced thickness and a guide shank fixed to said block, said block providing a bearing face for an adjacently mounted block said shank engaging in a bore to hold a face of the block in contact with the slide seat to prevent turning of the block relatively to the bar, and means on said shank for yieldably resisting sliding movement of the block relatively to said slide seat.

5. In a type carrier, in combination, a bar having spaced guide bores extending therethrough, part of the bar being reduced in thickness to present slide and limit faces, into which said bores open, type elements each presenting a block providing bearing surfaces for adj acently mounted blocks, a guide shank on the block, a slot in the block complementary to the bar for receiving the reduced part of the bar when the guide shank is positioned in a bore, and means associated with the shank for yieldably resisting movement of the block with respect to said slide and limit faces.

6. In a type carrier, in combination, a bar having spaced guide bores extending therethrough, contiguously mounted type elements each presenting a block of substantially the same thickness as said bar, the bar and the block each having portions reduced in thickness to present interfitting sections whereby the type elements and the bar have an assembled thickness substantially equal to the thickness of the bar, a guide shank on the block for engagement with a borev to hold the block and bar in assembled relation, and means for yieldably resisting a printing movement of said type element relatively to said bar.

3:57. :In a type arrangement, in oombinatio'n; a series of bars arranged in close sliding relation alongside each other, each bar having spaced bores extending widthwisetherethrough, and beingrednced in thickness to provide slide and lim it seatdportions, a plurality of typeeiements on each bar each presenting a block and a guide shank, the block providing'ibearing surfacestfor fldjacently supported blocks and having a portion'of reduced thickness arranged to engage the said seat portions when the guide shank rwts'in aqbore and projects therebeyond, and a spring carried by said projecting portion. of the shank for yieidably resisting printing movement of said type element. a r v 8.. r In a, type carrier, in combination, a bar hav ing spaced guide bores extending therethrough, part of the bar being reduced in thickness to present slide and limit faces into which said bores open, a plurality of contiguously supported type The following references are of record in the fiie of this patent:

UNITED STATES PATENTS Number Name 'Date 1,548,954 Pasinski Aug. 11, 1925 1,853,211 Hoffmann Apr. 12, 1932 Ford Oct. 30, 1934 

